Wednesday, October 2nd 2024
Crucial Discovers Flaw in AMD X670E Motherboards: Gen 5 NVMe Slots Drop to Gen 1 Speeds, Cause Boot Issues
Memory and SSD maker Crucial noticed an uptick in support requests by users claiming that their Gen 5 or Gen 4 NVMe SSDs would drop to PCIe Gen 1 speeds, besides being unable to boot into Windows after a restart. Crucial then did some digging, and localized the issue to users with motherboards based on the AMD X670E chipset, AMD's flagship Socket AM5 platform chipset. While not a function of the chipset itself, it turns out that there is a flaw in the way AMD designed the PCI-Express I/O of the X670E platform, specifically the PCIe Gen 5-capable M.2 NVMe interfaces that are attached to the CPU, causing them to drop in speeds to Gen 1. This problem isn't surfacing on the AMD B650 or the B650E, or even the X670—it is oddly specific to the X670E, despite the Gen 5 M.2 NVMe slots not being wired to the chipset.
While AMD made no public statement on the technical aspect of the flaw, if we were to guess, this could be a faulty implementation of PCIe ASPM (active state power management) at the firmware level, which reduces the speed of the PCIe link layer to reduce power. The default setting for PCIe ASPM in most motherboard UEFI setup programs tends to be "disabled," although there could be a bug in the firmware of X670E motherboards, causing it to engage, and in a buggy manner. Most UEFI BIOS setup programs tend to have two separate sets of PCIe ASPM settings—one for the CPU-attached PCIe root (which includes the x16 PEG and CPU-attached NVMe slots), and the other for downstream PCIe connectivity from the chipset.
Crucial suggested users to move their drives to the M.2 Gen 4 slots that are wired to the X670E chipset while they await UEFI firmware updates from their motherboard vendors. This works around the problem—at least you get Gen 4 x4 speeds if not Gen 1 x1. MSI is the first manufacturer to respond with UEFI firmware updates that correct the issue, letting users switch back to the faster CPU-attached Gen 5 NVMe slots. It remains to be seen if the issue affects the new AMD X870E, which launched earlier this week. The X870E is practically the same platform as the X670E.
Sources:
Wccftech, Notebookcheck
While AMD made no public statement on the technical aspect of the flaw, if we were to guess, this could be a faulty implementation of PCIe ASPM (active state power management) at the firmware level, which reduces the speed of the PCIe link layer to reduce power. The default setting for PCIe ASPM in most motherboard UEFI setup programs tends to be "disabled," although there could be a bug in the firmware of X670E motherboards, causing it to engage, and in a buggy manner. Most UEFI BIOS setup programs tend to have two separate sets of PCIe ASPM settings—one for the CPU-attached PCIe root (which includes the x16 PEG and CPU-attached NVMe slots), and the other for downstream PCIe connectivity from the chipset.
28 Comments on Crucial Discovers Flaw in AMD X670E Motherboards: Gen 5 NVMe Slots Drop to Gen 1 Speeds, Cause Boot Issues
I'm only surprised it's reported right now by Crucial and not any motherboard brand that reports full compatibility on their QVL lists. The issue has been around for over a year. I assume that barely anyone was using M.2 PCIe 5.0 SSDs because of ridiculous prices and not much better performance (out of synthetic benchmarks).
They've still not released an update for this on my motherboard yet (assuming it fixes the non-detected drive issue).
Well done Crucial finding the issue.
Is it only CRUCIAL NVME specific issue with the AMD X670E cpu wired NVME slot? Are other NVME brands also affected?
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I read it kinda often that some mainboards have issues with certain NVMes. I had the impression it was more an INTEL issue in the first place. Thanks for hinting out the bad NVME brands like WD (now SANDISK) and Samsung.
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Regarding the claim that ASUS ...: ASUS barely releases any up to date uefi updates for my X670 mainboard. Some updates are totally skipped by ASUS. The definition which board qualifies as high end or not depends on the user. A620 based am5 mainboards in my point of view are not high end.
Let's hope that thanks to Crucial's help, the other SSDs will also become usable ;-)
Congratulations on finally being able to use your hardware after 2 years and "EOL" of the platform.